Coaster brake



Oct. 23, 1951 H. l.. MUELLER 2,572,182

l COASTER BRAKE Filed June 20, 194

v. 1 `9L92524 El I5 INVENTOR.

A HOMER L.MULLER ATTORNEYS Patented Oct. 23, 1951 COASTER BRAKE Homer L. Mueller, Cleveland, Ohio, assigner to The Cleveland Welding Company, Cleveland, Ohio, a corporation of Ohio Application June zo, i946, serial No. 678,043

2 Claims. l The present invention relates as indicated to improvements in a coaster brake especially adapted for use on a bicycle or like vehicle.

One principal object of this invention is to provide a coaster brake which is extremely simple in structure .but yet is capable of efficiently performing all of the usual functions of such brakes, viz., propelling and stopping the vehicle and permitting coasting thereof at the will of the operator.

It is another object of this invention to provide a coaster brake having associated therewith a novel form of brake shoe mounting and actuating mechanism.

Additional objects and advantages of the invention will become apparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, said invention then comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the` annexed drawing setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principle of the invention may be employed.

In the drawing:

Fig. 1 is a central horizontal cross section view of my device showing the same in condition for propelling a bicycle;

Fig. 2 is a transverse cross section view through the brake shoes taken along line 2-2 of Fig. 1;

Fig. 3 is a fragmentary cross section View similar to that of Fig. 1 except showing the same in a brake shoe applying position;

Figs. 4 and 5 are fragmentary detail views of one end of the driving nut, Fig. 5 being a cross section View taken along line 5--5 of Fig 4; and

Fig. 6 is a transverse cross section view through the mechanism for firmly non-rotatably locking the axle to the frame of the bicycle, such view having been taken along line 6-6 of Fig. 1.

Referring now to the drawing, there is shown therein a portion of each of the spaced apart frame members I which constitute the rear fork of a bicycle across the ends of which an axle 2 extends. Axle 2 is firmly secured against movement longitudinally of its axis by means of nuts 3 and 5 disposed on opposite sides of each frame member I and in threaded engagement with the threaded ends of the axle. Suitable washers 4 are disposed between nuts 5 and one side of the members I. In order to non-rotatably secure axle 2 to the bicycle frame, one end thereof is formed with a transverse hole in which is fitted a key 6, the

radially projecting portion of which is fitted into an opening of complementary crossV section in one end of an arm 1. The other end of arm 'l is in turn firmly connected to one of the members I inta manner so well known to those skilled in the art that further illustration and explanation thereof is deemed unnecessary.

Mounted on said' axle 2 in spaced relation to one another are two rings 8 and 9, each of which con-V stitutes one of the races for a combination thrust and radial -ball bearing. Ring 8 is in threaded engagement with axle 2 and is locked longitudinally thereof by nut 3, while ring 9 is slidable on the, axle but non-rotatable thereon by reason of the slotted end I0 thereof fitting over the radial projecting portion of the key B.

Rotatably mounted on axle 2 is a driving screw II which has a counterbored end I2 forming the outer race for the balls I3 disposed between counterbore I2 and ring 8. Also mounted for rotation about axle 2 is a hub sleeve I4, the opposite counterbored ends I5 of which form the races for the balls I6 disposed between one counterbore I5 and ring 9 and between the other counterbore I5 and driving screw II. Hub sleeve I4 is, of course, provided with suitable apertured flanges for spokes I'l, which spokes are connected to the rim of the rear wheel of the bicycle, not shown.

It is now apparent that the hub sleeve I4 and the driving screw II are independently rotatable relative to axle 2. It is also apparent that by properly adjusting the ring 8 longitudinally of the axle, the hub sleeve can only rotate about an axis coincidental with that of axle 2 and cannot partake of longitudinal or tilting movement relative to such axis.

Within hub sleeve I4 is a pair of brake shoes I8 and a driving nut I9, the former being slidably mounted on the ends of a pin 20 fitted into a transverse hole in the axle andthe latter being in threaded engagement with the threaded end of the driving screw I I which projects into the hub sleeve. Pin 20 is preferably disposed horizontally so that the shoes I8, slidably carried by the ends thereof, will not tend by gravity to engage the inner cylindrical wall of the hu-b sleeve. The outer semi-cylindrical surface of each brake shoe is preferably formed with longitudinal serrations 2l therein to increase the friction when the same is urged into engagement with the inner wall of the hub sleeve. The inner surface of each brake shoe I8 is formed with a tapered wallV 22, both shoes together defining a frusto-conical wall adapted to be engaged with by the correspondingly tapered end 23 of the driving nut I9.

The hub sleeve I4 is also provided with a frustoconical surface 24 at its one end spaced from and facing toward the surfaces 22 of the brake shoes IB. The driving nut I9 is formed at its other end with 'a tapered surface 25 engageable with the surface 24 in the hub sleeve. End 25 of the driving nut is preferably serrated as clearly shown in Figs. 4 and 5 to assure a firmer lock between the driving nut I9 and the hub sleeve I4 than Iwould be possible between two perfectly smooth frusto-conical surfaces. The longitudinal spacing between surfaces 22 and 24 is greater than between the tapers 23 and 25 so that the driving nut I9 will be in engagement with either or none of them depending on whether it is desired to brake or to propel the vehicle or to permit coasting thereof respectively. The movement of driving nut I9 longitudinally in opposite directions will be presently described with greater particularity.

Secured to driving screw II is a sprocket wheel 2S which constitutes one element of the usualchain drive mechanism employed in most all bicycles. Sprocket wheel 26 is preferably in threaded engagement with driving screw il and is locked in place by means of a lock nut 21. Adjacent each end of hub sleeve I4 and secured respectively to ring 9 and to driving screw Il are dust caps 28 and 29 to exclude dirt from the ball bearings I6.

,It can now be seen that when the sprocket wheel 26 is rotated clockwise, as viewed from the right-hand end of Fig. 1, that rotation of driving screw II relative to driving nut I9 effects movement of the latter toward the right to the position shown in Fig. l, whereby continued rotation of the drive screw il effects, through the nut I9 and its engagement with tapered surface 24 of the hub sleeve I4, a driving of the hub sleeve in a clockwise direction to thus propel the bicycle in a forward direction.

Now, if the driving screw is rotated counterclockwise, as viewed from the right-hand end of Fig. 1, it can be seen that such rotation relative to driving nut I9 will effect movement of the latter toward the left into engagement with the tapered surfaces 22 of the brake shoes I8 to force the same apart in a radial direction into frictional engagement with the inner cylindrical wall of hub sleeve I4. In this way rotation of hub sleeve I4 relative to axle 2 is stopped or retarded as desired.

Of course, if the drive screw is rotated slightly clockwise from the brake shoe applying position described above, the driving nut I9 will move to a position between the tapered surfaces 22 and 24 whereby the hub sleeve I4 can freely rotate relative to axle 2 about the bearings I6. During propelling of the bicycle it is not necessary to actually rotate the driving screw il counter-clockwise to effect movement of the driving nut I9 to a coasting position but merely to discontinue clockwise rotation thereof, whereby the continued clockwise rotation of the hub sleeve I4 will, through the engagement of surfaces 24 and 25, effect rotation of the driving nut I9 relative to driving screw II to thereby disengage such surfaces.

It is to be observed that the relative rotation of the driving nut I9 and the driving screw II to enable propelling, braking, and coasting of the bicycle is effected solely by an inertia action whereby the nut I9 lags behind driving screw I! when the latter is rotated in either direction. Thus, all of the desired functions of the device are obtained without the use of springs or other resil'ent means.

As indicated above, the pin 20 is preferably disposed in a horizontal position so that when the driving nut is disengaged from the brake shoes I8, there will not be any drag of the brake shoes against the `hub sleeve I4, as would be the case if pin 20 were disposed in a vertical position.

As a matter of design, the bearing rings 9 and 9, the drive screw II and the driving nut i9 are preferably made of case hardened steel to resist wear. The hub sleeve I4 is preferably made of steel and the brake shoes I8 are preferably made of brass, such materials being selected for reasons of their desirable friction properties.

Key 6 and pin 29 are preferably press tted into their respective bores in the axle.

It is to be noted that the wear and deformation of the inter-engaged surfaces of the opening in arm 'I and of the radially projecting rectangular portion of the key 6 is minimized inasmuch as the contact pressure between such surfaces for a given torque is reduced to a point considerably less than what it would be if the usual connection were employed in which the axle has milled flats thereon and the arm has an opening of complementary cross section. This improved connection thus precludes loosening of the axle and arm connection so that the pin 29 will always be disposed horizontally as is desirable. This same rectangular portion of the key 6 being engaged in a slot in the ring 9 also holds the latter against rotation relative to the axle. Thus, it can be seen that I have provided an extremely simple and effective means for locking the axle 2 and the ring 9 against any rotation whatsoever relative to one another and to the bicycle frame.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims or the equivalent of such be employed.

I therefore particularly point out and distinctly claim as my invention:

l. A coaster brake comprising an axle including one pair of diametrically opposite and horizontally disposed radial projections, a hub shell and a driving screw each rotatably mounted on said axle, one pair of brake shoes slidably carried on such projections respectively for horizontal radial movement into and out of engagemen with said shell, and a nut having threaded engagement with said screw and alternately movable in opposite directions axially of said axle in response to rotation of said screw in opposite directions, said shoes and nut including interengageable cam surfaces operative when said nut is moved axially in one direction to cause radial movement of said shoes into frictional engagement with said shell to thereby resist rotation of said shell on said axle.

2. In a coaster brake for bicycles, the combination of an axle formed with a transverse hole of circular cross-section adjacent one end thereof, a pin fitted into such hole having a radial projection of non-circular cross-section presenting opposed parallel faces extending axially of said axle, a radially extending arm on said axle adapted for connection with a bicycle frame, said arm being formed with an opening therethrough non-rotatably embracing a portion of the opposed faces of the projection of said pin whereby to fix said axie against rotation, a ring on said axle adjacent to said arm formed with a radial slot also embracing a portion of the opposed faces of the projection of said pin whereby to non-rotatably lock said ring on said axle, a hub shell surrounding said axle, bearing means between said ring and shell rotatably supporting said shell on said axle, a brake element nonrotatably, radially movably carried by said axle for movement into frictional engagement within said hub shell to arrest rotation of said hub shell While said arm, through said pin, holds said axle and brake element thereon against rotation and While said pin holds said ring against rotation on said axle, and means for moving said brake element as aforesaid.

HOMER L. MUELLER.

REFERENCES CITED Number Name Date Willits May 16, 1899 2o Number Number 213,062 300,925

Name Date Gottschalk NoV. 9, 1909 Walker Aug. 8, 1911 Whittington Apr. l0, 1912 Walker Mar. 10, 1914 Lutze Jan. 19, 1915 Tobin Oct. 19, 1915 Schmidt Aug. 27, 1935 Schmidt July 20, 1937 Kurzina, Jr. Feb. 13, 1940 Lewis June 8, 1943 Walther et al Nov. 9, 1943 Garnett et al. Nov. 6, 1945 Hood Nov. 5, 1946 Goepfrich et al. July 5, 1949 FOREIGN PATENTS Country Date Great Britain Aug. 14, 1924 Germany Sept. 29, 1917 

